A typical corporate turbine aircraft environmental control system includes pressurization and temperature and generally is a function of bleed air introduced into the aircraft cabin from the engines. Since bleed air is hot, ambient ram air available during flight is usually used to cool it before use.
Two devices are commonly used for cooling engine bleed air, air cycle machines (ACM) and vapor cycle machines (VCM) or Freon units.
In an ACM, high pressure bleed air from the engines is passed through a compressor and then routed through a heat exchanger which is exposed to cold ram air to remove heat. An expansion chamber may be added to further cool the bleed air.
In a VCM, refrigerant such as Freon is compressed with a separate compressor into a hot high pressure liquid. The hot high pressure liquid is then drawn through an evaporator which interacts with cabin air through a heat exchanger. As the refrigerant evaporates, the heat exchanger cools the environmental air which is then routed to the cabin through a series of ducts.
In many cases, both ACMs and VCMs are installed and work together to provide environmental air to the cabin. However, neither the ACM nor the VCM is typically designed to work for long periods of time efficiently when the aircraft is on the ground. For example, the ACM requires ram air of extremely low temperature at high altitude in order to work efficiently. Similarly, VCM requires external cold air to augment the removal of heat from the heat exchanger. When cold ram air is not present, such as when the aircraft is on the ground, the efficiency of each system is reduced thereby increasing the temperature of environmental air to the cabin.
Air handling systems from VCRs typically rely on low voltage electric motors which drive impellers to circulate environmental air through the heat exchangers and return it to the cabin. However, the impellers are typically not designed for prolonged use alone and do not have high capacity.
Because of the reduced efficiency of the ACM and VCM while the aircraft is on the ground, environmental temperatures inside a cabin can reach uncomfortable levels if the air craft is required to be on the ground for long periods of time.
FIG. 1 shows the interior of a turbine aircraft of the prior art. The problem of cabin warming can be exacerbated by low airflow due to the improper duct placement. A typical ducting system for a turbine aircraft comprises a set of nozzles 102 at fixed overhead locations. These “face nozzles”, as they are known, operate only when the aircraft is in flight. In some aircraft, forward vents 104 are used to supply environmental air at temperature while the air craft is on the ground. However, these floor vents only supply environmental air in the center of the cabin, thereby reducing the airflow to the passengers and crew. Further, air return ducts are generally in the rear of the aircraft. Therefore, environmental air that is supplied by the forward floor vent is often drawn away by the rear return duct before proper circulation can be achieved.
FAA regulations require that air vents located in the floor of the aircraft be flush with the floor so as not to present a tripping hazard during an evacuation. As a result, cabin air directed upward from the floor vent is diffused into the surrounding cabin rather quickly, which reduces the air flowrate and apparent cooling to the passengers and crew.
As a result, there is a need for an airflow diverter that can redirect environmental air from a forward floor vent while the environmental system is operating at low capacity while the aircraft on the ground.
There is also a need for an air flow diverter that is in compliance with FAA standards for aisle safety and which does not present a tripping hazard.
The prior art discloses various venting devices intended to redirect airflow. Disadvantages of the prior art such as bulky components, complicated construction, and high manufacturing cost that make them ineffective solutions for the airflow problems of a corporate turbine aircraft.
For example, U.S. Patent Publication No. 2015/0241082 to Mosley discloses a tower floor register that replaces the standard in-floor register. The device comprises a plenum chamber base connected to stackable tower sections. Directional vents are attached to the top tower section. The base is permanently inserted into the floor opening. The tower can be stacked to different heights in order to clear an obstruction such as furniture.
U. S. Patent Publication No. 2009/0081941 to Reynolds discloses a floor vent attachment for redirecting airflow from a floor vent to avoid obstructions such as furniture. The device comprises a floor vent cover that is removably attached to a floor vent with magnets. An adjustable, flexible tubing is attached to the vent cover. A screen cover is affixed to the end of the flexible hose.
Japanese Publication No. JP 3140275U to Chong discloses a vertically oriented telescoping ventilation pipe for moving air between the floor and the ceiling of a room. The device is designed to move warm air from the ceiling down to the floor and cool air from the floor up to the ceiling. A ceiling register is connected to a floor register by the telescoping ventilation pipe. A reversible blower is integrated into the ventilation pipe to affect the direction of air flow.
However, none of these devices provide the many advantages of a stowable airflow redirect system as described.
Hence, there remains a need for an easily installed device for diverting cool air from the floor vent of a turbine aircraft for use while it is on the ground. Such a device should divert the cool air from the floor vent upward and directly into the cockpit area but yet be easily removable for cockpit exit safety.